This invention relates to the art of ink cartridges for ink jet printers and, more particularly, to an improved coupling device for connecting an ink supply line to an ink cartridge in a continuous ink supply system.
Continuous ink refill systems for disposable ink jet cartridges are of course well known as shown, for example, in U.S. Pat. No. 5,469,201 to Erickson, et al. and U.S. Pat. No. 5,745,137 to Scheffelin, et al., both of which are incorporated herein by reference for background information. In such systems, basically, a cartridge is connected to an auxiliary ink supply reservoir by means of a flexible hose or tube, and during operation of the printing system, the tube is open to allow ink to flow from the auxiliary reservoir to the ink cartridge. During shipment or handling of the ink supply reservoir/cartridge system when it is outside the print machine, it is important that the connection of the tube to the cartridge be leak tight to preclude the leakage of ink within the cartridge assembly and/or onto exterior surfaces of the cartridge and any box or container in which the ink supply reservoir system is packaged for transportation and storage. Moreover, after installation in the printer, cleaning of the latter and/or the ink delivery system requires removal of the cartridge from the printer, whereby the orientation of the cartridge may change from its upright position in the printer to an inclined or prone position relative to an underlying support surface. Accordingly, it is again essential to have a leakproof connection between the tubing and cartridge to avoid leakage of ink therefrom.
Prior efforts to seal the connection between the supply tubing and cartridge include extending the tube into the cartridge through an opening in an outer wall of the cartridge and gluing the tube in the opening to provide a seal and strain relief for the tubing, as shown for example in the aforementioned patent to Erickson. In the patent to Scheffelin, et al., tubing is coupled to a cartridge through the handle thereof by means of slidably interengaging tubular components which provide a seal against leakage of ink from the cartridge. In the latter arrangement, it is possible to unintentionally separate the coupling components so as to expose ink in the cartridge to spillage. Moreover, at least upon continued usage, wear of the slidably interengaging components could result in creating a leakage path or paths from the interior to the exterior of the cartridge. A coupling of the ink supply tube to an opening into the cartridge by gluing the tubing in place is of course subject to the creation of a leakage path across the glue in response to lateral flexure of the supply tube relative to the cartridge and/or as a result of tension applied to the tubing in the direction outwardly or inwardly of the cartridge.